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Proceedings Paper

Research of thermal cycles of long wavelength MCT infrared detectors
Author(s): Li-gang Wu; Da-fu Liu; San-gen Zhu; Hai-mei Gong
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Paper Abstract

The conflict of longevity of satellite's service and limited life of Sterling cooler decides that coolers should work on the intermittent mode in space. As a result, The HgCdTe (MCT) infrared (IR) detectors in satellite are commonly subjected to thousands of repeated thermal cycles from below -173°C to room temperature (20°C), which brings some new reliability problems. Especially the mismatch of coefficient of thermal expansion (CTE) of different materials may lead to some unfamiliar failure modes with such low temperature and nearly 200°C span of thermal cycles. In order to study the characteristics of MCT detectors under the stress of thermal cycles, this paper introduced a special automatic system. The system is mainly composed of a sub-container of liquid nitrogen, a heater controlled by the PID hardware, and an object stage on which the MCT detectors to be tested are mounted. Furthermore, the sub-container, the heater and the stage are positioned in a large vacuum tank. In the course of thermal cycles, the object stage moved up and down with MCT detectors is driven by a step motor. When it rises to the bottom of liquid nitrogen sub-container, the stage is to be cooled with detectors, and when declines to the heater, the stage to be heated with detectors, too. At last, two long wavelength MCT detector samples are tested with this equipment, and the resistance, the signal and the noise are measured. It shows that all the pixels' resistance didn't change beyond 5% after 5000 cycles. However, the tested signal of the last pixel of both detectors increased sharply after 1000 cycles, and fell to normal level after 5000 cycles, with its noise altering a little from beginning to end. A deduction is given in this paper for this phenomenon. In accordance, the thermal cycle equipment and the experimental data, would supply some references to the design and fabrication of MCT IR detectors.

Paper Details

Date Published: 4 August 2009
PDF: 6 pages
Proc. SPIE 7383, International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Infrared Imaging and Applications, 73831A (4 August 2009); doi: 10.1117/12.835864
Show Author Affiliations
Li-gang Wu, Ningbo Univ. (China)
Da-fu Liu, Shanghai Institute of Technical Physics (China)
San-gen Zhu, Shanghai Institute of Technical Physics (China)
Hai-mei Gong, Shanghai Institute of Technical Physics (China)

Published in SPIE Proceedings Vol. 7383:
International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Infrared Imaging and Applications
Jeffery Puschell; Hai-mei Gong; Yi Cai; Jin Lu; Jin-dong Fei, Editor(s)

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